Bleaching oils in the presence of steam



Patented Sept. 25,1951

BLEACHING OILS IN THE PRESENCE OF STEAM Roger M. Christensen, WhitefishBay, and Ralph E. Harpt, Wauwatosa, Wis., assignors to Pittsburgh PlateGlass Company No Drawing. Application December 22, 1950,

7 Serial No. 202,430

12 Claims. (Cl. 260-428) The present invention relates to a process ofimproving the quality of glyceride 'oils such as soya bean oil, linseedoil, cottonseed oil, peanut oil, corn oil, marine oil such as whale oil,menhaden oil, sardine oil, animal oils, such as lard, or the like and ithas particular relation to a process of treating such oils whichinherently are fairly low in break constituents for purposes ofimproving the color and also eliminating the last traces of break.

One object of the invention is to provide a process of treatingglyceride oils containing small amounts of break constituents as well asobjectionable coloring matter in order to eliminate or reduce theamounts of both constituents in a single simple one-stage operation.

A second object of the invention is to provide a process of treatingglyceride oils in order to remove break and color which does not requirealkali refining accompanied with the attendant losses of good oil in thefoots produced as a byproduct.

.A third object of the invention is to provide a process of treatingglyceride oils with activated absorbing agents which admits of the useof a substantially smaller amount of such agent than is required inconventional procedures and techniques.

A fourth object of the invention is to provide an oil from breakcontaining oil which will not poison conventional types of catalystsemployed in the preparation of alkyd resins or in the hydrogenation ofoils.

A fifth object of the invention is to provide at minimum expense aglyceride oil of light color and free from break, of a type highlydesirable for use in, fractionation technique.

A sixth object is to provide a process by application of which verydarkoils which do not bleach satisfactorily when subjected toconventional technique can be obtained in a condition satisfactory formost applications.

A seventh object is to provide a process by application of whichraffinate oils produced by liquid-liquid fractionation may be bleachedand rendered break free.

.These and other objects of the invention will be apparent fromconsideration of the following specification and the appended claims.

Conventional glyceride oils such as linseed oil, soya bean oil,cottonseed oil, corn oil, peanut oil and the like contain certainconstituents such as phosphatides and other gummy materials which tendto separate out, especially when the oil is subjected to heat, producinga gelatinous flock known as break. These break constituents also have atendency to poison the catalysts employed in the preparation of alkydresins. They further produce incrustations of carbonaceous materialsthat impair the color of the oils treated. In food oils, break mayprecipitate at inopportune times during processing to impair color andflavor, or to poison hydrogenation catalysts.

The oils further include coloring matter such as chlorophyll and otherconstituents which affect customer reaction adversely or which impairthe color of paints or varnishes. The presence of chlorophyll in foodoils which will be processed to salad oils or hydrogenated products islikewise objectionable, since it impairs the color and quality of thefinal product.

In order to obviate these defects in the oil it has heretofore beencustomary to subject the oil to refining operations, for example,treatment with caustic soda in order to remove the break constituentsand to form soaps of the fatty acids. Alkali refining also tends toimprove the color, which factor may be still further improved bytreating the oil with bleaching agents such as adsorbent clays orcarbons.

These conventional techniques are objectionable in various respects.Alkali refining, for example, results in excessive loss of oil in thesoap stock. Of course, there is also considerable expense involved inthe procurement of the requisite quantities of alkali for the operation.Substitute technique such as degumming by water hydration does notcompletely remove the break. The technique, as heretofore practiced, ofsubjecting the oil to bleaching after alkali refining, of course,introduces an additional step, addi-- tional costly material andrequiresmore apparatus. Furthermore, it is not effective for all type ofoil.

According to the present invention ithas been found that a glyceride oilcontaining break and/orcoloring matter can be subjected simultaneouslyto refining to' remove break and color by subjecting oil simultaneouslyto the action of steam and a bleaching agent such as fullers earth oractivated clay or other adsorbent at a temperature above the boilingpoint of water and thereafter removing moisture from the oil beforeremoval of the adsorbent, as for example by blowing the oil with inertgas. Under hydrating and bleaching conditions of the process, it isfound that all the break constituents and'gums can be removed from manyoils which contain reasonable amounts of such materials. It is alsofound that the activity of the agent, in many cases, is substantiallyimproved by the presence of the steam so that smaller amounts arerequired and it also becomes possible substantially to improve the colorof very dark oils which cannot be satisfactorily treated by conventionalmethods of decolorization.

THE OIL TO BE TREATED For purposes of the present inventionsubstantially any of the glyceride oils such as those above referred towhich contain not more than moderate amounts of break constituentsand/or objectionable coloring matter may be employed as a raw material.It is preferable that the break be present in comparatively small ormoderate proportions, e. g., 0.1% or less, or at most 0.3% as determinedby quantitative tests. some of the natural oils may be of sufficientlylow break to be employed without preliminary treatment. In otherinstances, where considerable amount of break is present in the raw oil,it may be desirable to degum, or partially degum it by conventionalhydration technique so as to reduce the break to a satisfactory value.In any event, the present process normally is applied to the treatmentof (but is not limited to) an oil which will give a, positive Gardnertest for break.

In this test a few drops of aqueous hydrochloric acid is added and theoil is heated to 550 F. Even a small amount of break in the oil willthen separate as an easily observable precipitate. If a quantitativetest is desirable, precipitate may be filtered off, washed free of oilwith carbon tetrachloride and weighed. The result is termed percentGardner break. The method is A. O. C. S. Ofiicial Method Ca 1040.

One type of oil which is excellently adapted to the practice of theinvention is that obtained as a rafiinate oil in the solventfractionation of a break containing oil such as ta partially degummedcrude soybean oil using furfural or like polar solvent for thefractionation. The rafiinate is quite low in free fatty acids but doesin most cases contain a small amount of gums or break constituents whichis, of course, objectionable.

The color of such rafiinate while improved over the original oil isusually not comparable to an alkali refined and bleached soybean oil. Inour process the use of steam and bleachingearth in one simple operationwill convert such raflinates to a break-free bleached oil which comparesfavorably to an alkali refined and bleached soybean oil in regard tocolor, odor, free fatty acid content, and actual conversion toshortenings and other food products. A ralfinate oil treated in thismanner may be hydrogenated to food products without poisoning thehydrogenation catalyst. Thus by a combination of solvent extraction andbleaching an oil in the presence of steam the oil may be fully refinedfor further processing into food products.

The fact that the use of fullers earth or other silica or silicateadsorbents and steam will cause a lowering of the free fatty acidcontent is especially of value in such products. For example, raffinateoils which have a free fatty acid content as high as 0.1% by weight areoften reduced to 0.05% or below upon steam bleaching with a fullersearth. This behavior is quite unique and is in distinction to ordinarybleaching techniques where at best the free fatty acid content remainsthe same and in many instances it actually is increased an objectionabledegree.

It is to be understood that many dark oils which are difiicult to bleachby ordinary methods, requiring large amounts of activated clay, yieldmuch more readily to the combinations of steam and earth as hereindisclosed. A glyceride oil that did not bleach satisfactorily with 5% ofacid activated clay was bleached satisfactorily with 2 to 3% by weightof earth when steam was blown into the oil containing it. If an oilcontaining chlorophyll is subjected to solvent fractionation most of thechlorophyll wil tend to go into the furfural phase and if the furfuralphase is evaporated directly the oil free of solvent will be darkin'color. Such dark oils may be difficult to decolorize under ordinarybleaching conditions but the use of steam and earth under the conditionsof our invention will yield oils of satisfactory color. The removal ofchlorophyll from any oil has been found to be easier when steam is usedin conjunction with the bleaching earth.

The use of the technique is also especially adapted to convertingdegummed crude soybean oils into light colored oils free of break whichfind ideal use in the manufacture of alkyd resins, varnishes, andrelated products. It is not imperative that such oils have an extremelylow free fatty acid content, so alkali refining or other refiningtreatment is not necessary in preparing these oils except to remove thebreak. The oils should be light in color, therefore a bleaching step isnecessary. Our process both bleaches and degums in one simple operationwith small losses. Such oils, light in color and free of break, are alsowell suited as feed oils for solvent fractionation processing to producea high iodine value extract and a low iodine value rafiinate.

THE ADSORBENT AGENT In the practice of the invention, various adsorbentagents as fullers earth such as that from Attapulgus, Ga., acidactivated bentonite or other adsorbent silica or silicate compositions,bone char, or activated charcoal or combinations thereof with fullersearth may be employed. The amount of the agent will vary, dependent uponthe amount of break and/or color in the oil, the activity in the agent,the degree of bleaching and other factors which may be desired. However,in most instances a proportion of 0.2 or 0.5 to 5% by weight of theagent may be employed. Some types of earth, e. g., acid activated claymay tend slightly to increase the acid value of the oil treated. Othersalmost as effective in decolorizing the oil do not appreciably increaseacidity and indeed, they may reduce acidity. From the examples tofollow, it Will be noted that in the case of fullers earths, thereduction of free fatty acid content is quite substantial.

THE TEMPERATURE AND CONDITIONS OF HYDRATION The temperatures to whichthe mixture is subjected during refining is susceptible of somevariation. Preferably, it is slightly above the temperature at whichwater boils at the pressure employed in the operation which is,preferably, atmospheric or near atmospheric pressures.

The pressure upon the system, of course, infiuences the temperature atwhich water boils. Generally the process is conducted at or nearatmospheric pressure. While slight vacuum (one or two pounds gauge) uponthe system is not objectionable, operation at high vacuum tends todehydrate the oil and therefore should be avoided. The process may beconducted at superatmospheric pressure, for example 10-15 pounds gaugeor even higher although no particular advantage appears to accruetherefrom. For most purposes, the temperature of the oil should beheldat a temperature between the temperature at which water boils under thepressure of the system and about 50 F. above this temperature, thepreferred range being about from the boiling point to 30 F. above thetemperature at which water boils. Hence the temperature of the oilundergoing treatment normally is maintained at 200 to 250 F., thepreferred range being about 215 to 230 or perhaps 242 F.

The oil normally is preheated to the temper-' ature of treatment priorto addition of adsorbent. This preheating may be eifected byintroduction of steam into the oil.

To efiect intimate contact of the oil with the steam and adsorbent,steam normally is introduced in the form of small bubbles by introducingthe steam through small orifices. Agitation of the mixture duringtreatment also facilitates this contact.

The process of bleaching andrendering an oil break free is onlyeffectual when operated under hydrating conditions, that is, whilemoisture is present in the oil. Satisfactory results are not achievedunder highly dehydrating conditions, such as exist when superheatedsteam is passed through the oil under high vacuum, as might be done indeodorizing an oil or in similar processes. A fairly substantial amountof water should be present. For example, if an oil-earth mixture afterbeing steamed by the present technique is subjected to filtrationwithout first drying, the oil will contain enough water to cause it tobecome cloudy when chilled to room temperature. Hence, even atatmospheric pressure, it has been observed that if the temperature ofthe bleaching be maintained too high, that break removal is incompleteand unsatisfactory. The conditions are apparently too anhydrous foreffective removal of the break. In another instance, it was found that ableach under a substantial vacuum in the presence of steam also wasineffectual in removing break. Again conditions were apparently tooanhydrous.

The rate of steam introduction upon mass basis i about 0.005 pound to .2pound per minute per 100 pounds of oil to be treated. Obviously the rateis not critical, since the range as above given is 40 fold from minimumto maximum.

It is desirable to maintain the oil under a blanket of inert gas such asnitrogen or carbon dioxide during the treatment with steam- The steammay simply be bubbled into a body of oil constituting a continuous phasepreheated to operating temperature. It alsois possible to inject a jetof water into hot oil so that it is converted to steam in situ. The 011containing the bleaching agent is blown fairly vigorously or subjectedto agitation in order to bring the combined bleaching and degummingoperation to a conclusion within a short period of time. If time is notof the essence, the blowing operation may be slowed down, Usually aperiodof 10 minutes to to 6 hours and preferably 30 minutes to 2 hoursis sufficient for most of the gum or break containing oils. The darkeroils require the greater periods of blowing while lighter oils arequickly brought to the desired color. Termination of the time requiredfor steam blowing can be easily determined by Gardner tests of the colorand for break. Blowingmay be continued so long as the color of samplescontinues to improve. Further blowing is needless.

When the oil has been adequately treated with steam, for example untilit is break negative as determined by the foregoing test, it should bedried in order to remove moisture introduced by steaming beforefiltering it. Such drying can be conveniently effected by blowing theoil with inert gas, e. g., carbon dioxide or nitrogen. The dryingoperation can be completed in a few, e. g., 10 to 30, minutes. However,the operation can be continued longer, though the costs of opera tionare increased thereby. This drying may be conducted at atmospheric orsubatmospheric pressure. The temperature of drying will vary withpressures of operation, rate of gas flow time permissible and suchfactors. A temperature of about 248 to 302 F. usually is effective.

When the oil is sufficiently dried, as can be determined by cooling asample and inspecting for the presence of moisture as evidenced byformation of a cloud in the oil, the oil may be filtered, with orwithout previously being cooled.

It should also be understood that the drying may be conducted withoutrecourse to inert gas.

Thus the water may be vaporized by heating the oil in vacuum until driedto the degree required. Dehydration agents may be added to the oil tofacilitate the drying.

Specific examples illustrating the application of the principles of theinvention are as follows:

Example 1 A solvent-extracted degummed soybean oil with a free fattyacid content of 0.215% by weight, a positive Gardner break test, aGardner color of 10, and an iodine Value of 135.9 may be treated.Apparatus for the operation comprises a convenient container such as akettle or column. It may be provided with means to preheat the oil and acoil of tubing or a jacket for circulation of a cooling medium. Thecontainer should also be provided with a steam supply head having minuteopenings and connections to a source of steam at desired temperature.Steam distribution may be enhanced by use of agitators and/or bafiles.Naturally, such meters as are required to measure temperatures in theoil, rates of .fiow of gases and pressures of steam and the like shouldalso be provided. It is convenient though not imperative to providemeans to supply blanketing inert gas to the apparatus.

The oil was heated in the apparatus to a temperature in the range of 200to 250 F., namely to about 230 F. Pre-heating of the oil could beeffected by heating coils or pipes or by open flame upon the containeror by merely blowing the oil with steam until operating temperature wasattained. Two percent by weight of an acid activated bleaching earth wasadded to the oil in the apparatus and steam was bubbled through theactivated mixture for two hours. The mixture was at atmospheric pressureduring this time. A stream of inert gas (from butane combustion) wasalso used to protect the oil from air. After the steam was discontinued,the mixture was heated at 230 F. with the inert gas bubbling through themixture for an extra 15 minutes to dry it well. The oil was filteredfrom the earth and the product had a free acid content of 0.431% byweight, a negative Gardner break test, and a Gardner color of 3. A testrun under identical conditions except the use of steam was omitted,yielded a well bleached oil ltauia one which still had a positiveGardner break Example 2 An expeller degummed soybean oil with 1.05% freefatty acids, a positive Gardner break test, and a Gardner color of 11was heated to 230 F. or thereabouts and under inert gas (from butanecombustion) in an apparatus as described in Example 1. Two percent byweight of an acid activated earth was added and steam was bubbledthrough the mixture for one hour at 230 F. The steam was thendiscontinued but the heat and the inert gas were maintained for fifteenminutes. The dry mixture was filtered and the resultant oil had a freefatty acid content of 1.15% by weight, a negative Gardner break test,and a Gardner color of 4.5.

Example 3 A solvent-extracted degummed soybean oil with a free fattyacid content of 0.24% by weight, a positive Gardner break test, and aGardner color of 10, and an iodine value of 133.5 was charged into anapparatus such as described in Example 1. It was heated to a temperaturewithin a range of 200 to 250 F., e. g., 230 F. Three percent by weightof a fullers earth was added and steam was bubbled in for one hour. Themixture was then dried for 15 minutes at about 230 F. with inert gasbubbling through the oil. The oil filtered from the earth had a freefatty acid content of 0.166%, a negative Gardner break test, and aGardner color of 6. Thereduction in free fatty acid content by the useof fullers earth is noteworthy.

Example 4 An oil resulting from the furfural fractionation of a degummedsoybean oil, with a free fatty acid content of 0.083%, a positiveGardner break test, a Gardner color of 8.5, and an iodine value of 131.8was charged into the apparatus as described in Example 1. It was heatedto 230 F. and was mixed with 2.5% by weight of a fullers earth. It wasthensubjected to a vigorous current of steam at about 230 F. for 20minutes. The steaming was discontinued and the mixture agitated for 5minutes under a stream of inert gas (from butane combustion). The dryearthoil mixture was then filtered to yield an absolutely break-free oilwith a Gardner color of 4 and a free fatty acid content of 0.022

In a similar test in which the same oil was treated under identicalconditions except that steaming was omitted, the resulting oil containeda large amount of break and 0.050% of free fatty acids.

Example 5 A raffinate oil resulting from the furfural fractionation of adegummed soybean oil with a free fatty acid content of 0.041% by weight,a positive Gardner break test, a Gardner color of 'l, and an iodinevalue of 129.9 was treated with 1.5% by weight of an acid activated clayand a vigorous current of steam at about 230 F. for 20 minutes. Thesteaming was discontinued and the mixture was agitated for 5 minutesunder a stream of inert gas. The dry earth-oil mixture was then filteredto yield an absolutely break-negative oil with a Gardner color of 2 anda free fatty acid content of 0.046% by weight.

Example 6 A raffinate oil resulting from the furfural fractionation of adegummed soybean oil with a free fatty acid content of 0.034% by weight,a positive Gardner break test, a Gardner color of 6, and an iodine valueof 125.7 was treated in an apparatus such as described in Example 1 with2.0% by weight of an acidactivated clay at about230 F. and atatmospheric pressure with a vigorous well: distributed flow of steam for20 minutes. The steaming was discontinued and the mixture was agitatedfor 5 minutesunder a stream of inert gas in order to dry it. The dryearth-oil mixture was then filtered to yield an absolutely breakfree'oil with a Gardner color of 2 and a free fatty acidcontent of 0.043% byweight.

Ewa'mple 7 A raffinate oil resulting from the furfural fractionation ofa degummed soybean oil with a free fatty acid content of 0.061% byweight, a positive Gardner break test, a Gardner color of 7, and aniodine value of 123 was heated to about 230 F. and 1% by weight of afullers earth was added. Steam at 230 F. was vigorously bubbled throughthe oil at atmospheric pressure for 20 minutes. The steaming wasdiscontinued and the mixture was agitated for 5 minutes under a streamof inert gas. The dry earth-oil mixture was then filtered to yield anabsolutely break-free oil with a Gardner color of 2.5 and a free fattyacid content of 0.046% by weight.

Example 8 A dark extract oil resulting from the furfural fractionationof degummed soybean oil had a free fatty acid content of 0.12% byweight, a Gardner color of 18+, an iodine value of 154.0 and no apparentbreak. The oil was heated to about 230 F. under inert gas, two percentby weight of an acid activated earth was added, and steam was introducedfor three hours while the oil was at or near atmospheric pressure. Thesteam was discontinued and the mixture was dried for several minutes andfiltered. The resultant oil had a Gardner color of 8 and a free fattyacid content of 0.31. The same experiment done without application ofsteam and with four percent by weight earth yielded an oil with anunacceptable color, that is, a Gardner value of 12, and a blackishtinge.

Example 9 A sample of extract oil resultin from the furfuralfractionation of a degummecl soybean oil having an original free fattyacid content of 0.18% by weight, a Gardner color of aboutv 18, and ablackish tinge, and an iodine value of 151.4 was introduced into theapparatus. It was bleached at about 230 F. and in the presence ofdistributed steam and inert gas and an acid activated earth for 4 /2hours. The pressure in the apparatus during these operations wasatmospheric. The mixture was then dried and filtered to yield an oilwith a Gardner color of 8.5 and a free fatty acid content of 0.48% byweight.

Example 10 A sample of crude peanut oil at about 230 F. was bleachedwith 2% by weight of an acid activated earth while steam was bubbledtherethrough for one hour. Agitation was continued for 15. minutes afterdiscontinuing the steam in order to dry the oil. Upon filtration the oilwas found to have a Gardner color of 3 and was break free.

Ewample 11 steam was then stopped and the mixture dried at 230 F. withinert gas bubbling through the mixture. The final product, afterfiltration of the earth, had a negative Gardner break test, 0.16

percent by weight of free fatty acids, a'Gardner color of 2, and uponhydrogenation gave a snow white shortening.

Example 12 A sample of oil obtained by the furfural fractionation ofcottonseed oil had the following properties; iodine value, 108.8;percentfree fatty acid, 0.12 by weight; Gardner break test, positive;Gardner color, 9-l0. One thousand grams of the oil were heated to about230 F'., twenty grams of fullers earth were added and live steam wasbubbled through. An inert gas (from butane combustion) was used as aprotective blanket. Agitation and steaming were continued for 1 hour.The steam was then stopped and the mixture dried by maintaining at 230F. with inert gas bubbling through the mixture. The final product, afterfiltration of the earth, had a negative Gardner break test, 0.10 percentby weight of free fatty acids, and a Gardner color of 3-4.

As previously intimated, the oil, when it has been properly blown withsteam, will contain small amounts of water which will separate as avisible cloud in the oil when the latter is cooled. It has been foundto'be desirable to subject the oil to a drying operation after it hasbeen subjected to steaming and before it is filtered. Drying results inan improved color and promotes ready filtration. Drying may be effectedin several different ways:

A. It can be blown with inert dry gas such as CO2 or nitrogen or amixture thereof.

B. The heated oil can be agitated until the moisture is evaporated, atleast to such degree that a cloud will not form therein when a sample iscooled.

C. The oil, preferably hot, can be placed under a vacuum to removemoisture.

These several methods are illustrated in the following example:

Example 13 A 2000 gram sample of degummed soya oil was placed in a fourliter stainless steel beaker having a rotary agitator and steamconnection near the bottom. It was heated to a temperature within arange of 230 to 239 F. 25.0 grams of acid activated earth known asSierra Absorbol A-420 and 25.0 grams of Attapulgus fullers earth wereadded. The oil, at atmospheric pressure, was blown with steam introducedbelow the agitator for minutes and the agitator was operated to effectthorough distribution and contact of the oil, adsorbent and steam.During bleaching, 4% by weight, based upon the oil, of steam was used.Steam was stopped and the sample was then divided into four parts forfiltration. One part was filtered while wet. The second was blown at 230to 239 F. with inert gas for 10 minutes to dry it. The third portion wasvigorously agitated for 10 minutes at 230 to 239 F. (no gas beingemployed) in order to dry it. The fourth portion was dried under avacuum of 20 millimeters (absolute) at a temperature of 194 to 212 F.over a period of 1 hour.

The samples were all filtered and color determinations were madethereupon by the use of a Coleman Spectrophotometer as recommended inthe June 1949 issue of the Journal of the American Oil Chemists Society.Under this system a I light colored oil has a low reading and a dark oila high reading. The results are tabulated as follows:

- Dried Dried Undrled Dried by With Under 011 Gas Agitatlon vacuumColeman Color 112 79 77 filtered without drying.

In the treatment of the oils as described in the examples, a certainamount of oil may tend to cling to the bleaching agent; this,howeveigmay in large measure be recovered by extraction with naphtha orother oil solvent. The coloring matter and break constituents are notappreciably taken up in naphtha. The loss of oil in the refiningoperations is only .1 to .2% if the clay is so treated. In any event thelosses will not be higher than in ordinary decolorization, even if thespent agent is not extracted. Alkali refining losses are usually inorder of 3 to 7%.

In most of the examples, blowing of the oil with inert gas in order todry it after it has been steam blown, has been described. A few minutesare usually sufficient to dry the oil. It is needless further to blowthe oil with gas after it has once been dried. However, there is noparticular limit upon the time or blowing, if it is desired further toblow it. Drying should be continued until the oil is bright and does notcloud when it is cooled to room temperature.

It will be apparent to those skilled in the art that numerousmodifications may be made herein without departure from the spirit ofthe invention or the scope of the appended claims.

This application is a continuation-in-part of our copending applicationSerial No. 41,168, filed July 28, 1948, which is now abandoned.

We claim:

1. A process of treating glyceride oil containing break constituents butin an amount not in excess of .3% which process comprises preheating theoil to a temperature of 215 to 242 F., then blowing it with live steamand in the presence .of about .2 to 5% by weight of an adsorbent earth,drying the oil by blowing it with inert gas, and removing the adsorbentearth.

2. A process as defined in claim 1 in which the adsorbent earth isfullers earth.

3. A process as defined in claim 1 in which the adsorbent earth is acidactivated clay.

4. A process as defined in claim 1 in which the oil treated is soybeanoil and the adsorbent earth is fullers earth.

5. A process of treating a glyceride oil containing break constituentsbut in an amount not in excess of 0.3% and coloring matter to obtain oilwhich is break negative and of improved color. which processcomprisesthe steps of preheating the oil to a temperature of 200 to 250 F., thenblowing it with steam and in the presence of about 0.2 to 5% by weightof an adsorbentbleaching earth, drying the oil by blowing it with inertgas, and then removing the adsorbent earth.

6. A method of treating a glyceride oil containing coloring matterinherent in a glyceride oil, to improve the color thereof, the breakcontent of said oil not exceeding .3% which method comprises the stepsof preheating the oil to a temperature of 200 to 250 F'., then blowingit with live steam in the presence of .2 to 5% by weight of an adsorbentbleaching earth, drying the oil by blowing it with inert gas, and.removing the adsorbent earth to obtain said oil of improved color.

'7. A process of treating a glyceride oil containing break constituentsbut in an amount not in excess of .3% and coloring matter inherent in aglyceride oil, which process comprises preheating the oil to atemperature of 200 to 250 F., then blowing it with live steam in thepresence of about .2 to 5% by weight of adsorbent bleaching material fora period of 10 minutes to 6 hours, drying the oil by blowing it withinert drying gas to remove water absorbed therein, then removing theadsorbent material whereby to obtain oil which is break negative and ofimproved color.

8. A process as defined in claim '7, in which the oil treated is soybeanoil, and the adsorbent material is fullers earth.

9. A process of treating a glyceride oil containing break constituentsbut not in excess of .3% and coloring matter inherent in a glycerideoil, which process comprises preheating the oil to a temperature of 200to 250 F. then blowing it with live steam in the presence of about .2 to5% by weight ofadsorbent bleaching material for a period of 10 minutesto 6 hours, then removing the moisture absorbed in 'the oil andsubsequently filtering the adsorbent material whereby to obtain oilwhich is break negative and of improved color.

10. A process of treating a glyceride oil containing break constituents,but not in excess of .3% by weight, and coloring matter inherent in aglyceride oil, which process comprises preheating the oil to atemperature of about 215 to 230 F., then blowing th oil with steam underhydrating conditions in the presence of about .2 to 5% of adsorbentbleaching material for a period of 10 minutes to 6 hours, then removingthe moisture absorbed in the oil and subsequently filtering off theadsorbent material, whereby to obtain oil which is break negative and ofimproved color.

11. The process as defined in claim 9 in which further good oil of lowcolor is obtained by extracting the spent adsorbent after the filteringoperation, with a solvent of oil.

12. A process of treating a glyceride oil containing break constituentsbut in an amount not in excess of 0.3%, which process comprisespreheating the oil to a temperature of 200 to 250 F'., then blowing itwith live steam and in the presence of 0.2 to 5% by weight of anadsorbent bleaching material, drying the oil of absorbed water andremoving the adsorbent.

ROGER M. CHRISTENSON. RALPH E. HARPT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,377,021 Mumford May 3, 19211,891,402 Craise et a1. Dec. 20, 1932 2,328,053 Buxton Aug. 31, 1943

1. A PROCESS OF TREATING GLYCERIDE OIL CONTAINING BREAK CONSTITUENTS BUT IN AN AMOUNT NOT IN EXCESS OF .3% WHICH PROCESS COMPRISES PREHEAT-ING THE OIL TO A TEMPERATURE OF 215 TO 242* F., THEN BLOWING IT WITH LIVE STEAM AND IN THE PRESENCE OF ABOUT .2 TO 5% BY WEIGHT OF AN ADSORBENT EARTH, DRYIUNG THE OIL BY BLOWING IT WITH INERT GAS, AND REMOVING THE ADSORBENT EARTH. 